Question

The Hubble Space Telescope has an aperture of 2.4m and focuses
visible light (400-700nm ). The Arecibo radio telescope in Puerto
Rico is 305m (1000 ft) in diameter (it is built in a mountain
valley) and focuses radio waves of wavelength 75 cm.

(a) Under optimal viewing conditions, what is the smallest crater
that each of these telescopes could resolve on our moon?